Since replacing the seal on the speedo drive is not documented in any forum that I could find, I gave it a go with my sub standard mechanical skills. There is a small seal (much like the tranny shift rod seal but half the size) inside the speedo drive housing and behind an NLA metal bushing. From what I could determine this bushing is pressed into the housing so there is no easy way to remove it so I got down and dirty with the vice grips after soaking it in Liquid Wrench for a day. Tighten the vice grips just enough so that you can twist the bushing in the housing (which is held with another set of pliers in a towel) like you are unscrewing it. Slowly work it back and forth while pulling up and it will eventually come out, the sides will be gouged by the vice grips but this is ok becaue the shaft does not contact them. Here is the bush out of the housing with the new seal next to them:
I then deburred and sanded any rough plier marks smooth and also polished where the shaft touches the face of the bush. I had the vice grips too tight and I distorted the opening a very small amount so I squeezed it 90 degrees opposite to make the hole round again, no problemo. This is the nasty old seal that I am sure would have leaked after all my 5 speed install efforts. Notice the seal is flush with the indented edge inside:
Removing was a bitch as it is very tight and no room to work with, I ended up cutting half the tip off a right angled pick seal, inserting it from the other side, then after catching the side of the seal I tapped it out. Like the shift rod seal, care must be taken not to score the metal. As seen i the first pic, I got it out and cleaned it all up.
Installing the new seal was treacherous, fortunately I have a history of destroying seals when installing them so I knew what to do here, and that is tap it VERY carefully, making sure one side does not start to creep in faster than another, otherwise you're toast if that happens. I used an 11mm deep socket on the ratchet side which seemed to fit nicely, important because the little bugger takes quite a pounding to get in there. The seal goes spring side up as in this pic:
Hit it flush and you're good to go. This is applicable to both 4 and 5 speed speedo drives.
I then deburred and sanded any rough plier marks smooth and also polished where the shaft touches the face of the bush. I had the vice grips too tight and I distorted the opening a very small amount so I squeezed it 90 degrees opposite to make the hole round again, no problemo. This is the nasty old seal that I am sure would have leaked after all my 5 speed install efforts. Notice the seal is flush with the indented edge inside:
Removing was a bitch as it is very tight and no room to work with, I ended up cutting half the tip off a right angled pick seal, inserting it from the other side, then after catching the side of the seal I tapped it out. Like the shift rod seal, care must be taken not to score the metal. As seen i the first pic, I got it out and cleaned it all up.
Installing the new seal was treacherous, fortunately I have a history of destroying seals when installing them so I knew what to do here, and that is tap it VERY carefully, making sure one side does not start to creep in faster than another, otherwise you're toast if that happens. I used an 11mm deep socket on the ratchet side which seemed to fit nicely, important because the little bugger takes quite a pounding to get in there. The seal goes spring side up as in this pic:
Hit it flush and you're good to go. This is applicable to both 4 and 5 speed speedo drives.
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